The invention relates to synergistic insecticidal mixtures of fipronil and agonists or antagonists of nicotinic acetylcholine receptors for the protection of industrial materials and as crop protection agents.
It is already known that fipronil can be employed for controlling wood-damaging animals (EP-295 117; U.S. Pat. No. 5,232,940). The very low vapour pressure of these compounds is an advantage.
However, relatively high concentrations are required when fipronil is used on its own. It is very difficult to deliver the concentrations required for activity sufficiently deep into the wood to be protected.
Furthermore, it is also known that agonists and antagonists of nicotinic acetylcholine receptors can be used for controlling insects and wood-damaging animals. Here, the active compound also has to be employed in relatively high concentrations to achieve an acute effect in the lower layers of the wood. In many instances, sub-lethal doses result in a change of the behaviour of the species, but in many cases these are reversible.
It has now been found that mixtures of fipronil and at least one agonist or antagonist of acetylcholine receptors of the formula (I) have synergistic activity and are suitable for protecting industrial materials, in particular wood, against attack by insects. These mixtures are also suitable in crop protection for controlling animal pests. Owing to this synergism, significantly lower amounts of active compounds can be used, i.e. the activity of the mixture is greater than the activity of the individual components.
The agonists and antagonists of the nicotinic acetylcholine receptors are known compounds, which are known from the following publications:
European Published Specifications Nos 464 830, 428 941, 425 978, 386 565, 383 091, 375 907, 364 844, 315 826, 259 738, 254 859, 235 725, 212 600, 192 060, 163 855, 154 178, 136 686, 303 570, 302 833, 306 696, 189 972, 455 000, 135 956, 471 372, 302 389;
German Offenlegungsschriften (German Published Specifications) Nos 3 639 877, 3 712 307;
Japanese Published Specifications Nos 03 220 176, 02 207 083, 63 307 857, 63 287 764, 03 246 283, 04 9371, 03 279 359, 03 255 072;
U.S. Pat. Nos. 5,034,524, 4,948,798, 4,918,086, 5,039,686, 5,034,404;
PCT Applications Nos WO 91/17 659, 91/4965;
French Application No. 2 611 114;
Brazilian Application No. 88 03 621.
The generic formulae and definitions described in these publications and the individual compounds described therein are expressly incorporated herein by reference.
Some of these compounds are summarized under the term nitromethylenes and related compounds.
Preferably, these compounds can be summarized under the general formula (I) 
in which
R represents hydrogen, optionally substituted radicals acyl, alkyl, aryl, aralkyl, heteroaryl or heteroarylalkyl;
A represents a monofunctional group from the series hydrogen, acyl, alkyl, aryl or represents a bifunctional group which is linked to the radical Z;
E represents an electron-withdrawing radical;
X represents the radicals xe2x80x94CHxe2x95x90 or xe2x95x90Nxe2x80x94, where the radical xe2x80x94CHxe2x95x90 may be linked to the radical Z instead of a H atom;
Z represents a monofunctional group from the series alkyl, xe2x80x94Oxe2x80x94R, xe2x80x94Sxe2x80x94R, 
xe2x80x83or represents a bifunctional group which is linked to the radical A or the radical X.
Particular preference is given to compounds of the formula (I) in which the radicals have the following meaning:
R represents hydrogen and represents optionally substituted radicals from the series acyl, alkyl, aryl, aralkyl, heteroaryl, heteroarylalkyl.
Examples of acyl radicals are formyl, alkylcarbonyl, arylcarbonyl, alkylsulphonyl, arylsulphonyl, (alkyl-)-(aryl-)-phosphoryl, which may themselves be substituted.
Examples of alkyl are C1-C10-alkyl, in particular C1-C4-alkyl, specifically methyl, ethyl, i-propyl, sec- or t-butyl, which may themselves be substituted.
Examples of aryl are phenyl, naphthyl, in particular phenyl.
Examples of aralkyl are phenylmethyl, phenethyl.
Examples of heteroaryl are heteroaryl having up to 10 ring atoms and N, O, S, in particular N, as hetero atoms. Specific examples are thiophenyl, furyl, thiazolyl, imidazolyl, pyridyl, benzothiazolyl.
Examples of heteroarylalkyl are heteroarylmethyl, heteroarylethyl having up to 6 ring atoms and N, O, S, in particular N, as hetero atoms.
Substituents which may be mentioned by way of example and by way of preference are:
alkyl having preferably 1 to 4, in particular 1 or 2, carbon atoms, such as methyl, ethyl, n- and i-propyl and n-, i- and t-butyl; alkoxy having preferably 1 to 4, in particular 1 or 2, carbon atoms, such as methoxy, ethoxy, n- and i-propyloxy and n-, i- and t-butyloxy; alkylthio having preferably 1 to 4, in particular 1 or 2, carbon atoms, such as methylthio, ethylthio, n- and i-propylthio and n-, i- and t-butylthio; halogenoalkyl having preferably 1 to 4, in particular 1 or 2, carbon atos and preferably 1 to 5, in particular 1 to 3, halogen atoms, the halogen atoms being identical or different, and preferred halogen atoms being fluorine, chlorine or bromine, in particular fluorine, such as trifluoromethyl, hydroxyl; halogen, preferably fluorine, chlorine, bromine and iodine, in particular fluorine, chlorine and bromine, cyano; nitro; amino; monoalkyl- and dialkylamino having preferably 1 to 4, in particular 1 or 2, carbon atoms per alkyl group, such as methylamino, methylethylamino, n- and i-propylamino and methyl-n-butylamino; carboxyl, carbalkoxy having preferably 2 to 4, in particuar 2 or 3, carbon atoms, such as carbomethoxy and carboethoxy; sulpho (xe2x80x94SO3H); alkylsulphonyl having preferably 1 to 4, in particular 1 or 2, carbon atoms, such as methylsulphonyl and ethylsulphonyl; arylsulphonyl having preferably 6 or 10 aryl carbon atoms, such as phenylsulphonyl, and also heteroarylamino and heteroarylalkylamino such as chloropyridylamino and chloropyridylmethylamino.
A represents hydrogen and optionally substituted radicals from the series acyl, alkyl, aryl, which are preferably as defined above, A furthermore represents a bifunctional group. Examples include optionally substituted alkylene having 1 to 4, in particular 1 or 2, C atoms, examples of substituents being the substituents which have been mentioned further above.
A and Z together with the atoms to which they are attached may form a saturated or unsaturated heterocyclic ring. The heterocyclic ring may contain a further 1 or 2 identical or different hetero atoms and/or hetero groups. Preferred hetero atoms are oxygen, sulphur or nitrogen, and preferred hetero groups are N-alkyl, where the alkyl of the N-alkyl group contains preferably 1 to 4, in particular 1 or 2, carbon atoms. Examples of alkyl include methyl, ethyl, n- and i-propyl and n-, i- and t-butyl. The heterocyclic ring contains 5 to 7, preferably 5 or 6 ring members. Examples of the heterocyclic ring include pyrrolidine, piperidine, piperazine, hexamethylenimine, morpholine and N-methylpiperazine.
E represents an electron-withdrawing radical, specific examples being NO2, CN, halogenoalkylcarbonyl such as 1,5-halogeno-C1-C4-carbonyl, in particular COCF2.
X represents xe2x80x94CHxe2x95x90 or xe2x80x94Nxe2x95x90
Z represents optionally substituted radicals alkyl, xe2x80x94OR, xe2x80x94SR, xe2x80x94NRR, where R and the substituents are preferably as defined above.
Z, together with the atom to which it is attached and the radical 
xe2x80x83instead of X, may form a saturated or unsaturated heterocyclic ring. The heterocyclic ring may contain a further 1 or 2 identical or different hetero atoms and/or hetero groups. Preferred hetero atoms are oxygen, sulphur or nitrogen and preferred hetero groups are n-alkyl, where the alkyl or N-alkyl group contains preferably 1 to 4, preferably 1 or 2, carbon atoms. Examples of alkyl include methyl, ethyl, n- and i-propyl and n-, i- and t-butyl. The heterocyclic ring contains 5 to 7, preferably 5 or 6, ring members. Examples of the heterocyclic ring include pyrrolidine, piperidine, piperazine, hexamethylene-imine, morpholine and N-methylpiperazine.
The agonists and antagonists of the nicotinic acetylcholine receptors are preferably compounds of the formula (I)
R represents 
where
n represents 1 or 2,
Subst. represents one of the abovementioned substituents, especially halogen, in particular chlorine, and A, Z, X and E are each as defined above.